Walking into a drone-fighting pit is much like walking into a boxing ring. The audience looks on as pilots on either side make last-minute preparations, swapping out propellers and tucking in loose cables before the round begins. With a smooth flick of the joysticks, the drones zoom into the air. They sway from left to right, right to left, as if anticipating what the other will do. A moment’s carelessness and one of the warriors is on the ground, its propellers torn and its motors screeching in a futile attempt at liftoff. The winner hovers above, victorious.

It's a form of aerial combat that is known among drone fighters as Game of Drones. The rules are straightforward: Each drone starts off with three points. You lose a point every time your drone hits the ground, and the first to reach zero points loses. If both drones collapse, it’s what’s known as a “push,” and in that case neither competitor loses a point. If your drone is unable to fly, you get 90 seconds to fix it before the match is declared over.

The sport began in 2013 when a group of robot makers, designers, and engineers got the idea to form a drone fight club. It quickly gained popularity, attracting dozens of people from around the world and eventually morphing into a formal organization called Aerial Sports League (ASL).

At first glance, smashing together drones worth a couple of hundred dollars each doesn't seem like the smartest idea. But aside from the plastic propellers, the drones are pretty indestructible. One drone fighter said his had survived a shotgun blast.

The Game of Drones website offers consumers two drone kit options for about US$400 each. The two kits are identical except for the color of the airframe, but they can be customized. This is what's included in a kit:

Four RCManchild 2212 1000KV motors

Four RCManchild 30Amp SimonK-firmware electronic speed controllers

One KK 2.0 HC flight board with programmer

One Hobby King Octocopter power distribution board

One frame cap

Four propellers

In addition to drone combat, the Aerial Sports League also sponsors many first-person-view drone-racing events.